Chain grate stoker



April 12, 1932. H. J. KERR CHAIN GRATE STOKER Filed Aug. 20, 1926 y E zur Patented Apr. 12, 1932 UNITED STATES PATENT oFF-'ics HOWARD J.' KERR, OF WESTFIELD, NEW JERSEY, ASSIGNOR T0 THE BABCOCK & WILCOX COJNIPANY, F BAYONNE, NEXV JERSEY, A CORPORATION 0]? NEV JERSEY' y CHAIN GRATE STOKER Application filed August 20, 1926.

cates the lower portion of a furnace that is shown broken. away. A chain grate Stoker' having an upper run 2 and a lower run 3 is located below the furnace chamber proper, in the usual manner, and the chain grate Stoker passes over Sprockets that are mounted on a driving shaft 4 and a driven shaft 5, in the manner well known in this art. Transverse I-beams 6 extend across the furnace below the upper run 2 of the chain grate, and support the Same. Plates 7 are pivoted to the lower flanges of the I-beams 6, and these plates rest upon the upper side of the lower run 3 of the chain grate Stoker, so that the I- beams 6 and plates 7 divide the space between the runs of the Stoker into compartments, into which combustion air may be introduced, and thence pass upwardly through the upper run of the chain grate stoker in a manner well known.

A drag plate 8 is located below the lower run 8 of'the chain grate Stoker, and is supported by transverse I-beams 9, so that the lower run of the Stoker will pass along the upper surface of the drag plate 8. Bafles 10 extend upwardly from the bot-tom plate 11 and are located between the I-beams 9 with their upper edges extending some distance above the lov-Jer edges of these l-beams. rlhe bottom plate 11 may be provided with a plurality of openings having cover plates or doors 11 through which dust and soot may be withdrawn. Some of the I-beams 9, for example, the firstand last ones of the series, may he provided with holes 12 in the webs thereof.

Air is admitted to the space 18 in any convenient manner, as by openings in the front plate as illustrated. The Space 18 is located near the front of the furnace casing o beneath the hopper 14, and also beneath the Serial No. 130,370.

sprocket on the driving shaft 4, The rear' ends of the plates 8 and 11 are connected by a transverse plate., and one orV moreoutlets 15 extend from this plate to a header 16 that is connected to a suction fan 17, the outlet 18 of which may lead to the furnace;

The operation is as follows: Coal is fed by means of the hopper 14 upon the upper run 2 of the chain grate stoker, and is, carried toward the left, as indicated in the drawing, into the lower portion of the furnace where it is ignited, the ashes and clinker being carried to the rear end and falling into the ashpit in the usual manner. The lower run 8 of of the chain grate Stoker passes along the drag plate 8, carrying siftings toward the right, and finally` over the rightshand end. of the drag plate 8, from which they fall into lthe ashpit. Air entering the space 13 passes inrpart through theopenings 12 in the webs of the I-beams 9, and in part below the lower edges of these I-beams, and over the upper edges of the baffles 10 ina sinuous path, as indicated by the arrows, thus impinging against the lower side of the drag plate 8 and. cooling the same, as well as cooling the links of the lower run 3 of the chain grate Stoker as the heat therefrom is transmitted through the plate k8. The air passes in a direction countercurrent to the direc-A tion of travel of the lower run 3 of the chainl grate stoker, and becomes more and more heated until it passes out thro-ughthe outlets 15, header 16, fan 17 and outlet 18, into the furnace, lwhere the heated air is used for combustion purposes.

Dust and soot that may enter with the air are thrown out between the baffles 10 and settle on the platerll, from which they may be withdrawn at intervals through the doors 11. The fan 17 in drawing the cold air longitudinally through the space between-the plat/es 8 and 11 causes a slight Suction at the front end of the Stoker. This decreases the tendency for dust to escape from the furnace, thus keeping the boiler room clean. As air is drawn in through small crevices that frequently occur in the front casing of stokers, this avoids the'objection that frequently occurs, because pressures greater than atmospheric inside the furnaces often cause dust to be forced out through crevices. On the contrary, the decreased pressure produced by this device causes the air to be drawn inwardly and prevents dust and ashes from escaping into the boiler room.

I claim:

l. In a furnace provided with a chain grate stoker, a drag plate for the lower run of said Stoker, transverse I-beams to support said drag plate, some of said I-beams being provided with holes through the webs thereof, and means to pass air into contact with the lower side of said drag plate and through said holes.

2. In a furnace provided with a chain grate stoker, a drag plate for the lower run of said Stoker, means to pass air longitudinally beneath said drag plate in a stream, and means to 'direct sai'dstream at intervalsfagainst said pla-te,"V

3. In avfurnace, a chain grate Stoker, a duct'extending longitudinally of said Stoker for substantially the entire length thereof and beneath the lower run thereof, means for passing air through said duct, and a pluralityv of,l baffles on the Ylower wall of said duct to direct the `air passing therethrough against p the upper wall.

Il.' In a furnace provided with a chain grate Stoker, 'a drag plate for the lower run of said Stoker, transversev supports for said drag plate, a bottom plate disposed beneathsaid drag plate 'and spaced therefrom to form a duct, baflles disposed in said duct between said supports and cooperating with the supportsi andplates to form a sinuous path, and meansto pass air along Saidpath into Contact with the lower side of said drag plate.

5.' In a furnace provided with a chain grate Stoker, a drag plate for the lower run of saidstoker, transverse supports for said drag plate,fa plate disposed 'beneath said drag plate and Yspaced therefrom, baflies disposed bei tween Said supports and forming with the supports and plates a sinuous path, means to pass air along 'said path into Contact with the lower side yof said dragv plate, and means whereby soot and dust may be removed from between 'said baes.

` ofthe Stoker and an outlettherefor disposed nea'rthe rear ofthe Stoker, and -ineans for passing air through said duct from the inlet to the outlet.

8. In a furnace, a chain grate stoker, a duct extending longitudinally of said Stoker and )eneath the lower run thereof, the top of the duct contacting with Said lower run, an inlet for said duct disposed near the front of the Stoker, and an outlet therefor disposed near the rear of the Stoker, and means for passing air through said'duct from the inlet to the outlet, said means being disposed at the outlet end of the duct.

HOI/VARI) J. KEER. 

